Good luck starting this puzzle.
You'll stop where you always do.
My middle is in the ending.
You can see on the outside that I skipped school,
but beneath that you'll find I'm deeper.

What am I?

Hints 1:

Your best shot is to start with my beginning and ending. Some users here have already identified those. "My middle is in the ending" probably won't make sense until you find my ending. If you strip away the parts of me that refer to skipping school, you'll find something that could mean the same thing as "deeper."

$\begingroup$Nice! This is my first puzzle on the site, hope you and others enjoyed it$\endgroup$
– RaceYouAnytimeOct 12 '19 at 16:04

3

$\begingroup$@RaceYouAnytime - I thought this question was great and hope you write more. Earlier answerers (before the hints) such as PiIsNot3 and JS1 deserve the credit for working through this puzzle. Also, Stiv and Avi's posts were excellent.$\endgroup$
– TomOct 12 '19 at 16:21

2

$\begingroup$the skipped school part is highly locale-dependent$\endgroup$
– njzk2Oct 13 '19 at 19:12

Not sure about this one. Maybe the middle/infix is AR, which is a part of the suffix?

You can see on the outside that I skipped school,

The outer letters spell GE, which could stand for “general education.” In the US, you can “skip” high school by taking a GED (general education development) test. Probably too tenuous to be valid, though.

but beneath that you'll find I'm deeper.

No clue on this one at all. “Beneath” probably indicates the inner part, which is LAR, but I can’t find any connection between that and being deeper.

Title: Stare long enough and you will have found the answer

Glare is a synonym for stare, meaning fixating your gaze on something for a long time.

I stare at you, you are a cover/guard/barrier, there can be a rear-view mirror in the middle of you, your outside is flat, you are flat (dull, dumb) because of skipping school, you are deeper beyond the flat surface (physical extension)

Perhaps a bit far-fetched, but I found this to be a reasonably good fit too:

sleep

Stare long enough and you will have found the answer

Eventually you'll fall asleep.

Good luck starting this puzzle.

You will always start this puzzle while being awake, the opposite of sleep.

You'll stop where you always do.

Sleep always stops when waking up, which usually happens in bed.

My middle is in the ending.

After you die (ending), you'll be in the middle of an eternal sleep. OR: Sleep usually occurs in repetitive cycles, governed by having one or multiple REM/awakening stages in the middle and at the end.

You can see on the outside that I skipped school,

If someone is sleeping during school hours, it is likely this person is skipping school. Furthermore, sleep is not condoned in school.